Started off by
- Enabling unattended updates
- Enable only ssh login with key
- Create user with sudo privileges
- Disable root login
- Enable ufw with necessary ports
- Disable ping
- Change ssh default port 21 to something else.
Got the ideas from networkchuck
Did this on the proxmox host as well as all VMs.
Any suggestions?
from the internet side, I lock down ssh or administrative stuff to local network, and specific IPs, like work. inside my network, everything has a password to access, no defaults. vlans for specific use servers, etc.